Methods for depositing material onto microfeature workpieces in reaction chambers and systems for depositing materials onto microfeature workpieces

ABSTRACT

Methods for depositing material onto microfeature workpieces in reaction chambers and systems for depositing materials onto microfeature workpieces are disclosed herein. In one embodiment, a method includes depositing molecules of a gas onto a microfeature workpiece in the reaction chamber and selectively irradiating a first portion of the molecules on the microfeature workpiece in the reaction chamber with a selected radiation without irradiating a second portion of the molecules on the workpiece with the selected radiation. The first portion of the molecules can be irradiated to activate the portion of the molecules or desorb the portion of the molecules from the workpiece. The first portion of the molecules can be selectively irradiated by impinging the first portion of the molecules with a laser beam or other energy source.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 10/840,571 filed May 6, 2004, now U.S. Pat. No. 8,133,554, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention is related to methods for depositing material onto microfeature workpieces in reaction chambers and systems for depositing materials onto microfeature workpieces. More particularly, the present invention is related to methods for irradiating a portion of a microfeature workpiece to desorb or activate molecules in that portion of the workpiece.

BACKGROUND

Thin film deposition techniques are widely used in the manufacturing of microfeatures to form a coating on a workpiece that closely conforms to the surface topography. The size of the individual components in the workpiece is constantly decreasing, and the number of layers in the workpiece is increasing. As a result, both the density of components and the aspect ratios of depressions (i.e., the ratio of the depth to the size of the opening) are increasing. Thin film deposition techniques accordingly strive to produce highly uniform conformal layers that cover the sidewalls, bottoms, and corners in deep depressions that have very small openings.

One widely used thin film deposition technique is Chemical Vapor Deposition (CVD). In a CVD system, one or more precursors capable of reacting to form a solid thin film are mixed while in a gaseous or vaporous state, and then the precursor mixture is presented to the surface of the workpiece. The surface of the workpiece catalyzes the reaction between the precursors to form a solid thin film at the workpiece surface. A common way to catalyze the reaction at the surface of the workpiece is to heat the workpiece to a temperature that causes the reaction.

Although CVD techniques are useful in many applications, they also have several drawbacks. For example, if the precursors are not highly reactive, then a high workpiece temperature is needed to achieve a reasonable deposition rate. Such high temperatures are not typically desirable because heating the workpiece can be detrimental to the structures and other materials already formed on the workpiece. Implanted or doped materials, for example, can migrate within the silicon substrate at higher temperatures. On the other hand, if more reactive precursors are used so that the workpiece temperature can be lower, then reactions may occur prematurely in the gas phase before reaching the substrate. This is undesirable because the film quality and uniformity may suffer, and also because it limits the types of precursors that can be used.

Atomic Layer Deposition (ALD) is another thin film deposition technique. FIGS. 1A and 1B schematically illustrate the basic operation of ALD processes. Referring to FIG. 1A, a layer of gas molecules A coats the surface of a workpiece W. The layer of A molecules is formed by exposing the workpiece W to a precursor gas containing A molecules and then purging the chamber with a purge gas to remove excess A molecules. This process can form a monolayer of A molecules on the surface of the workpiece W because the A molecules at the surface are held in place during the purge cycle by physical adsorption forces at moderate temperatures or chemisorption forces at higher temperatures. Referring to FIG. 1B, the layer of A molecules is then exposed to another precursor gas containing B molecules. The A molecules react with the B molecules to form an extremely thin layer of solid material on the workpiece W. The chamber is then purged again with a purge gas to remove excess B molecules.

FIG. 2 illustrates the stages of one cycle for forming a thin solid layer using ALD techniques. A typical cycle includes (a) exposing the workpiece to the first precursor A, (b) purging excess A molecules, (c) exposing the workpiece to the second precursor B, and then (d) purging excess B molecules. In actual processing, several cycles are repeated to build a thin film on a workpiece having the desired thickness. For example, each cycle may form a layer having a thickness of approximately 0.5-1.0 Å, and thus several cycles are required to form a solid layer having a thickness of approximately 60 Å.

One drawback of ALD processing is that it has a relatively low throughput compared to CVD techniques. For example, each A-purge-B-purge cycle can take several seconds. This results in a total process time of several minutes to form a single thin layer of only 60 Å. In contrast to ALD processing, CVD techniques require only about one minute to form a 60 Å thick layer. The low throughput limits the utility of the ALD technology in its current state because ALD may create a bottleneck in the overall manufacturing process.

FIG. 3 schematically illustrates a single-wafer CVD/ALD reactor 10 having a reaction chamber 20 coupled to a gas supply 30 and a vacuum pump 40. The reactor 10 also includes a gas dispenser 60 and a heater 50 for supporting the workpiece W in the reaction chamber 20. The gas dispenser 60 includes a plenum 62 operably coupled to the gas supply 30 and a distributor plate 64 having a plurality of holes 66. In operation, the heater 50 heats the workpiece W to a desired temperature, and the gas supply 30 selectively injects the precursors as described above. The vacuum pump 40 maintains a negative pressure in the reaction chamber 20 to draw the gases from the gas dispenser 60 across the workpiece W and then through an outlet of the chamber 20.

In photoselective CVD processing, the reaction chamber 20 may further include a laser 70 configured to generate a laser beam 72 for activating at least one of the precursors. The laser 70 produces the laser beam 72 along a beam path generally parallel to the workpiece W, with the laser beam 72 positioned between the gas dispenser 60 and the workpiece W to selectively activate a precursor(s) before the precursor(s) is deposited onto the workpiece W. The activated precursor(s) subsequently reacts with other precursors on the surface of the workpiece W to form a solid thin film.

In addition to CVD and ALD processing, other processing steps are necessary to form features and devices on workpieces. For example, conventional processing includes patterning a design onto a workpiece, etching unnecessary material from the workpiece, depositing selected material onto the workpiece, and planarizing the surface of the workpiece. These additional processing steps are expensive and time-consuming. Accordingly, a need exists to improve the efficiency with which features are formed on workpieces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic cross-sectional views of stages in ALD processing in accordance with the prior art.

FIG. 2 is a graph illustrating a cycle for forming a layer using ALD techniques in accordance with the prior art.

FIG. 3 is a schematic representation of a system including a reaction chamber for depositing materials onto a microfeature workpiece in accordance with the prior art.

FIG. 4 is a schematic representation of a system for depositing materials onto a microfeature workpiece in accordance with one embodiment of the invention.

FIGS. 5A-5C illustrate stages in an ALD process in which a laser desorbs material from a workpiece in accordance with another embodiment of the invention.

FIG. 5A is a schematic side cross-sectional view of a portion of the workpiece after depositing a layer of first molecules onto a surface of the workpiece.

FIG. 5B is a schematic side cross-sectional view of the workpiece after desorbing a selected portion of the first molecules.

FIG. 5C is a schematic side cross-sectional view of the workpiece after depositing a layer of second molecules onto the workpiece.

FIGS. 6A-6D illustrate stages in a CVD process in which the laser desorbs material from a workpiece in accordance with another embodiment of the invention.

FIG. 6A is a schematic side cross-sectional view of a portion of the workpiece after depositing a layer of first molecules onto a surface of the workpiece.

FIG. 6B is a schematic side cross-sectional view of the workpiece after with the laser desorbing selected first molecules from a portion of the workpiece.

FIG. 6C is a schematic side cross-sectional view of the workpiece after depositing second molecules onto the workpiece.

FIG. 6D is a schematic side cross-sectional view of the workpiece after desorbing a selected portion of the second molecules.

FIGS. 7A-7C illustrate stages in an ALD process in which the laser activates molecules on a workpiece in accordance with another embodiment of the invention.

FIG. 7A is a schematic side cross-sectional view of a portion of the workpiece after depositing a layer of first molecules onto the workpiece.

FIG. 7B is a schematic side cross-sectional view of the workpiece after depositing a plurality of second molecules onto the workpiece.

FIG. 7C a schematic side cross-sectional view of the workpiece after removing the nonreacted second molecules from the workpiece.

FIG. 8 is a schematic representation of a system for depositing materials onto a microfeature workpiece in accordance with another embodiment of the invention.

FIG. 9 is a schematic representation of a system for depositing materials onto a microfeature workpiece in accordance with another embodiment of the invention.

DETAILED DESCRIPTION

A. Overview

The following disclosure describes several embodiments of systems for depositing materials onto microfeature workpieces, and methods for depositing materials onto workpieces in reaction chambers. Many specific details of the invention are described below with reference to single-wafer reaction chambers for depositing materials onto microfeature workpieces, but several embodiments can be used in batch systems for processing a plurality of workpieces simultaneously. The term “microfeature workpiece” is used throughout to include substrates upon which and/or in which microelectronic devices, micromechanical devices, data storage elements, read/write components, and other features are fabricated. For example, microfeature workpieces can be semiconductor wafers such as silicon or gallium arsenide wafers, glass substrates, insulative substrates, and many other types of materials. Furthermore, the term “gas” is used throughout to include any form of matter that has no fixed shape and will conform in volume to the space available, which specifically includes vapors (i.e., a gas having a temperature less than the critical temperature so that it may be liquefied or solidified by compression at a constant temperature). Several embodiments in accordance with the invention are set forth in FIGS. 4-9 and the following text to provide a thorough understanding of particular embodiments of the invention. A person skilled in the art will understand, however, that the invention may have additional embodiments, or that the invention may be practiced without several of the details of the embodiments shown in FIGS. 4-9.

Several aspects of the invention are directed to methods for depositing materials onto microfeature workpieces in a reaction chamber. In one embodiment, a method includes depositing molecules of a gas onto a microfeature workpiece in the reaction chamber and selectively irradiating a first portion of the molecules on the microfeature workpiece in the reaction chamber with a selected radiation without irradiating a second portion of the molecules on the workpiece with the selected radiation. The first portion of the molecules can be irradiated to activate the molecules or desorb the molecules from the workpiece. The first portion of the molecules can be selectively irradiated by impinging the molecules with a laser beam or another energy source.

In another embodiment, a method includes depositing first molecules of a first gas onto the microfeature workpiece in the reaction chamber, directing a laser beam toward a first portion of the first molecules to desorb the first portion of the first molecules without desorbing a second portion of the first molecules, and depositing second molecules of a second gas onto the second portion of the first molecules. The first and second gases can have generally the same or different compositions. The method can further include directing the laser beam toward a first portion of the second molecules to desorb the first portion of the second molecules without directing the laser beam toward a second portion of the second molecules.

In another embodiment, a method includes depositing first molecules of a first gas onto the microfeature workpiece in the reaction chamber, directing a laser beam toward a selected portion of the first molecules to activate the selected portion of the first molecules to react with second molecules of a second gas, and depositing the second molecules of the second gas onto the selected portion of the first molecules. The first and second gases can have the same or different compositions. The method can further include purging excess first gas from the reaction chamber before depositing molecules of the second gas.

Other aspects of the invention are directed to systems for depositing materials onto a surface of a microfeature workpiece. In one embodiment, a system includes a gas supply assembly having a gas source, a gas phase reaction chamber for carrying the microfeature workpiece, a gas distributor carried by the reaction chamber and coupled to the gas supply assembly, an energy source positioned to selectively irradiate portions of the microfeature workpiece, and a controller operably coupled to the energy source and the gas supply assembly. The controller has a computer-readable medium containing instructions to perform one of the above-mentioned methods.

B. Embodiments of Deposition Systems

FIG. 4 is a schematic representation of a system 100 for depositing materials onto a microfeature workpiece W in accordance with one embodiment of the invention. In this embodiment, the system 100 includes a reactor 110 having a reaction chamber 120 coupled to a gas supply 130 and a vacuum pump 140. The reactor 110 also includes a gas distributor 160 coupled to the gas supply 130 to dispense gas(es) into the reaction chamber 120 and onto the workpiece W. Byproducts including excess and/or unreacted gas molecules are removed from the reaction chamber 120 by the vacuum pump 140 and/or by injecting a purge gas into the chamber 120.

The gas supply 130 includes a plurality of gas sources 132 (shown schematically and identified individually as 132 a-c) and a plurality of gas lines 136 coupled to corresponding gas sources 132. The gas sources 132 can include a first gas source 132 a for providing a first gas, a second gas source 132 b for providing a second gas, and a third gas source 132 c for providing a third gas. The first and second gases can be first and second precursors, respectively. The third gas can be a purge gas. The first and second precursors are the gas and/or vapor phase constituents that react to form the thin, solid layer on the workpiece W. The purge gas can be a suitable type of gas that is compatible with the reaction chamber 120 and the workpiece W. In other embodiments, the gas supply 130 can include a different number of gas sources 132 for applications that require additional precursors or purge gases.

The system 100 of the illustrated embodiment further includes a valve assembly 133 (shown schematically) coupled to the gas lines 136 and a controller 134 (shown schematically) operably coupled to the valve assembly 133. The controller 134 generates signals to operate the valve assembly 133 to control the flow of gases into the reaction chamber 120 for ALD and CVD applications. For example, the controller 134 can be programmed to operate the valve assembly 133 to pulse the gases individually through the gas distributor 160 in ALD applications or to mix selected precursors in the gas distributor 160 in CVD applications. More specifically, in one embodiment of an ALD process, the controller 134 directs the valve assembly 133 to dispense a pulse of the first gas (e.g., the first precursor) into the reaction chamber 120. Next, the controller 134 directs the valve assembly 133 to dispense a pulse of the third gas (e.g., the purge gas) to purge excess molecules of the first gas from the reaction chamber 120. The controller 134 then directs the valve assembly 133 to dispense a pulse of the second gas (e.g., the second precursor), followed by a pulse of the third gas. In one embodiment of a pulsed CVD process, the controller 134 directs the valve assembly 133 to dispense a pulse of the first and second gases (e.g., the first and second precursors) into the reaction chamber 120. Next, the controller 134 directs the valve assembly 133 to dispense a pulse of the third gas (e.g., the purge gas) into the reaction chamber 120. In other embodiments, the controller 134 can dispense the gases in other sequences.

In the illustrated embodiment, the reactor 110 also includes a workpiece support 150 to hold the workpiece W in the reaction chamber 120. The workpiece support 150 can be heated to bring the workpiece W to a desired temperature for catalyzing the reaction between the first gas and the second gas at the surface of the workpiece W. For example, the workpiece support 150 can be a plate with a heating element. The workpiece support 150, however, may not be heated in other applications.

The illustrated reaction chamber 120 further includes a laser 170 (shown schematically) operably coupled to the controller 134 for producing a laser beam 172 to irradiate selected portions of the workpiece W. The laser beam 172 provides sufficient localized energy to desorb or activate the irradiated molecules on the workpiece W. For example, after a layer of material has been deposited onto the workpiece W, the laser 170 can direct the laser beam 172 toward a selected portion of the material to desorb or activate the material, as described in greater detail below. Depending on the material, the power required for desorption can be on the order of 1e6 W/cm². Accordingly, in several embodiments, the laser 170 can be a stand-alone laser system; and in other embodiments, the laser 170 can include one or more laser diodes. For example, suitable laser diodes include a 600 W QCW Laser Diode Array, part number ARR48P600, manufactured by Cutting Edge Optronics in St. Charles, Mo. In additional embodiments, the reaction chamber 120 may include an energy source in lieu of a laser to heat a localized portion of the workpiece W for desorbing or activating selected molecules.

The reactor 110 may further include a positioning device 180 (shown schematically) coupled to the laser 170 and operably coupled to the controller 134 for moving the laser 170 and aligning the laser beam 172 with the selected portion of the workpiece W. For example, the positioning device 180 can move the laser 170 from a stowed position (shown in hidden lines) to a deployed position (shown in solid lines) for irradiating the selected portion of the workpiece W. In the stowed position, the laser 170 and the positioning device 180 are arranged so as not to interfere with the flow of gases from the gas distributor 160 to the workpiece W. The positioning device 180 can be configured to move the laser 170 side to side (e.g., X direction) and forward and backward (e.g., Y direction) to align the laser beam 170 with the selected portion of the workpiece W. Alternatively, the positioning device 180 may also be able to move the laser 170 upward and downward (e.g., Z direction). The positioning device 180 can accordingly have an articulating arm, a telescoping arm, or other type of structure to support the laser 170 over the workpiece W. The positioning device 180 can further include an actuator to move the arm. In other embodiments, such as those described below with reference to FIGS. 8 and 9, the reactor may not include a positioning device coupled to the laser.

C. Embodiments of Methods for Depositing Materials Onto Workpieces

FIGS. 5A-5C illustrate stages in an ALD process in which the laser 170 desorbs material from the workpiece W in accordance with one embodiment of the invention. FIG. 5A, more specifically, is a schematic side cross-sectional view of a portion of the workpiece W after dispensing a pulse of a first gas into the reaction chamber 120 (FIG. 4) and depositing a layer of first molecules 192 from the first gas onto a surface 190 of the workpiece W. FIG. 5B is a schematic side cross-sectional view of the workpiece W with the laser beam 172 impinging a selected portion P₁ of the workpiece W. After depositing the first molecules 192 onto the workpiece W, the positioning device 180 aligns the laser 170 with the selected portion P₁ of the workpiece W and the laser 170 directs the laser beam 172 toward selected first molecules 192 a. The power, wavelength, and other laser beam parameters are selected based on the chemistry of the first molecules 192 so that the energy from the laser beam 172 breaks the bonds securing the selected first molecules 192 a to the surface 190 and, consequently, desorbs the selected first molecules 192 a from the workpiece W. As the laser 170 moves across the workpiece W, the laser beam 172 impinges the selected first molecules 192 a without impinging a plurality of nonselected first molecules 192 b. Consequently, the nonselected first molecules 192 b remain physisorbed and/or chemisorbed to the surface 190 of the workpiece W.

After irradiating the portion P₁ of the workpiece W, a purge gas can be dispensed into the reaction chamber 120 (FIG. 4) to remove the desorbed first molecules 192 a and the excess first gas molecules from the chamber 120. Alternatively, the purge gas can be dispensed into the reaction chamber 120 while the portion P₁ of the workpiece W is irradiated. In other embodiments, the desorbed first molecules 192 a can be removed from the reaction chamber 120 without injecting a purge gas by drawing the molecules 192 a from the chamber 120 with the vacuum pump 140 (FIG. 4). In additional embodiments, the desorbed first molecules 192 a can be removed from the reaction chamber 120 as a second gas is subsequently injected into the chamber 120 and deposited onto the workpiece W.

FIG. 5C is a schematic side cross-sectional view of the workpiece W after dispensing a pulse of a second gas into the reaction chamber 120 (FIG. 4) and depositing a layer of second molecules 194 from the second gas onto the workpiece W. The second molecules 194 react with the first molecules 192 b to form a discrete film 195 a on the workpiece W.

The first and second gases can have the same or different compositions. For example, in one embodiment, the composition of the second molecules 194 can be chosen such that the second molecules 194 adhere to the nonirradiated first molecules 192 b but do not adhere to the exposed portion P₁ of the surface 190. Suitable gases for such an embodiment include TMA for the first gas and O₃ for the second gas, although other gases can be used. In other embodiments, the second molecules 194 can adhere to the exposed portion P₁ of the surface 190 in addition to the nonirradiated first molecules 192 b. If some of the second molecules 194 adhere to the exposed portion P₁ of the surface 190, the laser 170 (FIG. 4) can optionally irradiate and desorb these molecules. In either case, after depositing the second molecules 194 onto the workpiece W, the reaction chamber 120 can be purged and the process can be repeated to build additional layers (shown in hidden lines as 195 b and 195 c) on the workpiece W.

In additional embodiments, the laser 170 can irradiate the selected portion P₁ of the workpiece W only after the second molecules 194 have been deposited onto the workpiece W. For example, in one method, the first molecules 192 are deposited across the workpiece W, and then the reaction chamber 120 can be optionally purged. Next, the second molecules 194 are deposited across the workpiece W, and then the laser 170 irradiates the selected portion P₁ of the workpiece W to desorb the selected first and second molecules.

One advantage of the method illustrated in FIGS. 5A-5C is the ability to form features 199, such as conductive lines, on the workpiece W during an ALD process. Forming features 199 on the workpiece W during the deposition process simplifies and reduces the number of subsequent production steps required to construct devices on the workpiece W. For example, by forming the features 199 on the illustrated workpiece W during an ALD process, post-deposition processing, including masking, etching, depositing material, and planarizing, may be reduced and/or eliminated.

FIGS. 6A-6D illustrate stages in a CVD process in which the laser 170 desorbs material from the workpiece W in accordance with another embodiment of the invention. FIG. 6A, more specifically, is a schematic side cross-sectional view of a portion of the workpiece W after dispensing a pulse of one or more precursors into the reaction chamber 120 (FIG. 4), mixing the precursors to form a gas, and depositing a layer of first molecules 292 from the gas onto the surface 190 of the workpiece W. FIG. 6B is a schematic side cross-sectional view of the workpiece W with the laser 170 directing the laser beam 172 toward selected first molecules 292 a to desorb the molecules 292 a from a portion P₂ of the workpiece W. As the laser 170 moves across the workpiece W, the laser beam 172 does not impinge and desorb a plurality of nonselected molecules 292 b. After desorption, the selected first molecules 292 a can be removed from the reaction chamber 120 by dispensing a purge gas into the chamber 120 and/or drawing the desorbed molecules 292 a from the chamber 120 with the vacuum pump 140 (FIG. 4). Alternatively, the purge gas can be dispensed into the reaction chamber 120 while the portion P₂ of the workpiece W is irradiated.

FIG. 6C is a schematic side cross-sectional view of the workpiece W after dispensing another pulse of the precursors into the reaction chamber 120 (FIG. 4), mixing the precursors to form the gas, and depositing a plurality of second molecules 294 of the gas onto the workpiece W. The second molecules 294 are deposited onto the nonirradiated molecules 292 b and the exposed portion P₂ of the workpiece W. The second molecules 294 proximate to the first molecules 292 b react with the first molecules 292 b to form a discrete film 295 a on the workpiece W.

FIG. 6D is a schematic side cross-sectional view of the workpiece W with the laser 170 directing the laser beam 172 toward selected second molecules 294 a to desorb the selected molecules 294 a from the portion P₂ of the workpiece W. After desorbing the selected second molecules 294 a, the process can be repeated to build additional layers (shown in hidden lines as 295 b and 295 c) on the workpiece W. In other embodiments, the selected second molecules 294 a may not be desorbed from the workpiece W or may be desorbed during subsequent process steps.

In additional embodiments, more than one layer of molecules can be desorbed during a single irradiation cycle. For example, in one method, a layer of first molecules 292 can be deposited onto the workpiece W, a layer of second molecules 294 can be deposited onto the workpiece W, and then the laser beam 172 can desorb the selected first and second molecules 292 a and 294 a from the workpiece W.

FIGS. 7A-7C illustrate stages in an ALD process in which the laser 170 activates molecules on the workpiece W in accordance with another embodiment of the invention. More specifically, FIG. 7A is a schematic side cross-sectional view of a portion of the workpiece W after dispensing a pulse of a first gas into the reaction chamber 120 (FIG. 4) and depositing a layer of first molecules 392 (shown as 392 a and 392 b) from the first gas onto the surface 190 of the workpiece W. After depositing the first molecules 392, the reaction chamber 120 can optionally be purged to remove excess molecules of the first gas. Next, the laser 170 moves across the workpiece W and directs the laser beam 172 toward selected first molecules 392 a on a portion P₃ of the workpiece W. The power, wavelength, and other laser beam parameters are selected based on the chemistry of the first molecules 392 so that the energy from the laser beam 172 activates the selected first molecules 392 a such that the molecules 392 a are inclined to react with a subsequent gas. More specifically, the energy from the laser beam 172 breaks one or more of the bonds of the selected adsorbed molecules 392 a, which destabilizes the molecules 392 a such that the molecules 392 a are inclined to react with the next molecule in the ALD sequence. As the laser 170 moves across the workpiece W, the laser beam 172 activates the selected first molecules 392 a without exposing or activating a plurality of nonselected first molecules 392 b on the workpiece W.

FIG. 7B is a schematic side cross-sectional view of the workpiece W after dispensing a pulse of a second gas into the reaction chamber 120 (FIG. 4) and depositing a layer of second molecules 394 (shown as 394 a and 394 b) from the second gas onto the workpiece W. The first and second gases can have the same or different compositions. The second molecules 394 a proximate to the activated first molecules 392 a react with the activated molecules 392 a to form a discrete film 395 on the workpiece W. The second molecules 394 b proximate to the nonactivated first molecules 392 b generally do not react with the nonactivated molecules 392 b.

FIG. 7C a schematic side cross-sectional view of the workpiece W after removing the nonreacted second molecules 394 b (FIG. 7B) from the workpiece W. The nonreacted second molecules 394 b can be removed from the workpiece W and the reaction chamber 120 (FIG. 4) by dispensing a purge gas into the chamber 120 and/or drawing the molecules 294 b from the chamber 120 with the vacuum pump 140 (FIG. 4). In some embodiments, the nonactivated first molecules 392 b can also be removed from the workpiece W; however, in other embodiments, the nonactivated first molecules 392 b may not be removed from the workpiece W. In either case, the process can be repeated to build additional layers (shown in hidden lines as 395 b and 395 c) and form a feature 399 on the workpiece W.

In other embodiments, the laser 170 can irradiate the selected portion P₃ of the workpiece W after the second molecules 394 have been deposited onto the workpiece W. For example, in one method, a layer of first molecules 392 are deposited across the workpiece W, and then the reaction chamber 120 can be optionally purged. Next, a layer of second molecules 394 are deposited across the workpiece W, and then the laser 170 irradiates the selected portion P₃ of the workpiece W to activate the selected first and/or second molecules and catalyze the reaction between the selected molecules.

In additional embodiments, the methods described above with reference to FIGS. 7A-7C can also be used in a CVD process. For example, in one CVD process, a layer of first molecules can be deposited onto a workpiece, and the laser can activate a selected portion of the first molecules. Next, a plurality of second molecules can be deposited onto and react with the activated first molecules. Alternatively, as described above, the laser can irradiate the selected portion of the workpiece after a layer of second molecules have been deposited to catalyze the reaction between the selected first and second molecules.

D. Additional Embodiments of Deposition Systems

FIG. 8 is a schematic representation of a system 400 for depositing materials onto a microfeature workpiece W in accordance with another embodiment of the invention. The illustrated system 400 is generally similar to the system 100 described above with reference to FIG. 4. For example, the illustrated system 400 includes a reactor 410 having a reaction chamber 420 coupled to the gas supply 130 and the vacuum pump 140. The illustrated reaction chamber 420 includes a laser 470 (shown schematically) for producing a laser beam 472 along a path, a reflector 478 positioned along the path of the laser beam 472, and a positioning device 480 (shown schematically) for moving the reflector 478 relative to the workpiece W. The laser 470 can be fixed relative to the workpiece W and configured to pivot about the Z axis. The positioning device 480 can move the reflector 478 side to side (e.g., X direction) and forward and backward (e.g., Y direction) to reflect the laser beam 472 toward the selected portion of the workpiece W.

FIG. 9 is a schematic representation of a system 500 for depositing materials onto a microfeature workpiece W in accordance with another embodiment of the invention. The illustrated system 500 is generally similar to the system 100 described above with reference to FIG. 4. For example, the illustrated system 500 includes a reactor 510 having a reaction chamber 520 coupled to the gas supply 130 and the vacuum pump 140. The illustrated reaction chamber 520 includes a laser 570 (shown schematically) for generating a laser beam 572 (shown in hidden lines), a workpiece support 150 for carrying the workpiece W, and a positioning device 580 (shown schematically) attached to the workpiece support 150 for moving the workpiece W relative to the laser 570. For example, the positioning device 580 can move the workpiece support 150 from a first position (shown in solid lines) in which the workpiece W is oriented for deposition to a second position (shown in broken lines) in which the workpiece W is oriented for irradiation.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. For example, any one of the systems 100, 400 and 500 described above with reference to FIGS. 4, 8 and 9 can be used to perform any one of the methods described above with reference to FIGS. 5-7. Accordingly, the invention is not limited except as by the appended claims. 

We claim:
 1. A system for forming features on a microfeature workpiece by depositing materials onto a surface of the microfeature workpiece, the system comprising: a gas supply assembly having a gas source; a gas phase reaction chamber for carrying the microfeature workpiece; a gas distributor carried by the reaction chamber and coupled to the gas supply assembly; an energy source positioned to selectively irradiate portions of the microfeature workpiece, wherein the energy source comprises a laser configured for producing a laser beam; and a controller operably coupled to the energy source and the gas supply assembly, the controller having a computer-readable medium containing instructions and configured to perform a method comprising— depositing a monolayer or approximately a monolayer of molecules of a gas onto the microfeature workpiece in the reaction chamber, wherein the molecules of the gas comprise a plurality of first molecules of a first gas; selectively irradiating a first portion of the first molecules on the microfeature workpiece in the reaction chamber with a laser beam having a selected radiation without irradiating a second portion of the first molecules on the workpiece with the selected radiation, wherein selectively irradiating the first portion comprises desorbing the first portion of the first molecules from the workpiece; depositing second molecules of a second gas onto the second portion of the first molecules, wherein the first gas and the second gas have different compositions; and repeating the depositing and selectively irradiating to form a feature on the workpiece.
 2. The system of claim 1, further comprising a positioning device coupled to the laser, wherein the positioning device is configured to move the laser to selectively direct the laser beam toward the first portion of the microfeature workpiece.
 3. The system of claim 1, further comprising a reflector positioned in the path of the laser beam to reflect the laser beam toward the microfeature workpiece.
 4. The system of claim 1 wherein the system further comprises: a reflector positioned in the path to reflect the laser beam toward the microfeature workpiece; and a positioning device coupled to the reflector for moving the reflector so that the reflector directs the laser beam toward the first portion of the microfeature workpiece.
 5. The system of claim 1 wherein the system further comprises: a workpiece support for carrying the microfeature workpiece; and a positioning device coupled to the workpiece support for moving the support to align the microfeature workpiece with the laser beam.
 6. The system of claim 5 wherein the workpiece support is further configured to heat the workpiece to a desired temperature during operation.
 7. The system of claim 1 wherein the gas source of the gas supply assembly comprises a first gas source configured to supply the first gas, and wherein the gas supply assembly further comprises a second gas source configured to provide the second gas.
 8. The system of claim 7 wherein the first gas comprises a first precursor and the second gas comprises a second precursor.
 9. The system of claim 8 wherein the gas supply assembly further comprises a third gas source configured to provide a third gas, and wherein the third gas comprises a purge gas. 